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I'm using an ST Microelectronics LIS3DSH accelerometer to detect tilt over an extended period of time. I have the accelerometer securely mounted to a stationary object away from any vibration. Over the course of two and a half days, I've found the readings slowly change in value. I've made sure it's not a defective accelerometer by performing this experiment multiple times using different accelerometers but the same exact manufacturer and part number.

Below are graphs of the type of drift I see over time. You'll notice a change of about 0.006G on X, 0.009G on Y and .05G on Z. Note in the final graph below, the magnitude continually drops over time. I have no idea why this is. It should always be 1 or very close to 1.

Two questions:

  1. Is this a common or known phenomenon with accelerometers?
  2. Could anyone recommend an accelerometer similar to the LIS3DSH where this undesirable behavior would not occur?

Thanks in advance for any information anyone might be able to provide.

Accelerometer's X Reading Accelerometer's Y Reading Accelerometer's Z Reading Accelerometer's Magnitude

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    \$\begingroup\$ Is it following the temperature? You are showing variation at thousandths of a g. The datasheet gives values for temperature dependent stuff in that range. \$\endgroup\$ – JRE Nov 5 '19 at 15:47
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    \$\begingroup\$ Is it following the tides? (I admit that this may be an ignorant question.) Can you try mounting the sensors with different orientations with respect to vertical? \$\endgroup\$ – Elliot Alderson Nov 5 '19 at 15:50
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    \$\begingroup\$ Do you have more than one unit? accelerometers do drift though but it should be bounded. the changes you measure are real small \$\endgroup\$ – DKNguyen Nov 5 '19 at 15:58
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    \$\begingroup\$ @TerenceD sounds like you might want an electrolytic tilt sensor instead for such a static, sensitive application. more accurate and stable. more $$$ too \$\endgroup\$ – DKNguyen Nov 5 '19 at 16:28
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    \$\begingroup\$ It is interesting to note that the typical applications are for relatively short time frames; the device contains factory calibration data that are loaded each time the device is powered on. Have you tried turning it off for a while and then turning it back on? \$\endgroup\$ – Peter Smith Nov 5 '19 at 17:08
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If you tried testing multiple units and they all drift at the same rate, you might try using two of them (in similar temperature and pressure environments) to measure the difference in relative tilt between the object under test and some fixed reference point.

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